相关疑难解决方法(0)

PPA 似乎一直处于离线状态。每当我使用时sudo apt-get update，都会显示此错误：

W: Failed to fetch http://ppa.launchpad.net/ 404  Not Found

如何修复这些错误？

我设置了一个 Lucid Server (10.04)，我想将镜像从美国（或任何其他国家/地区）更改为主 Ubuntu 镜像。

例如，我在 sources.list 中的两个第一个条目是：

deb http://us.archive.ubuntu.com/ubuntu/ lucid main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ lucid main restricted

在桌面环境中，我会像这样选择主镜像：

但是我如何从终端执行此操作，因为我没有安装图形环境！

W: Invalid 'Date' entry in Release file /var/lib/apt/lists/_var_cuda-repo-8-0-local_Release
N: Skipping acquire of configured file 'non-free/binary-arm64/Packages' as repository 'http://repository.spotify.com stable InRelease' doesn't support architecture 'arm64'
E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial/main/binary-arm64/Packages  404  Not Found [IP: 91.189.88.161 80]
E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial-updates/main/binary-arm64/Packages  404  Not Found [IP: 91.189.88.161 80]
E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial-backports/main/binary-arm64/Packages  404  Not Found [IP: 91.189.88.161 80]
E: Failed to fetch http://archive.ubuntu.com/ubuntu/dists/xenial-security/main/binary-arm64/Packages  404  Not Found [IP: 91.189.88.161 80]
E: Some index files failed to download. They have been ignored, or …

从 15.10 升级到 16.04 后，我收到以下错误apt-get update：

Reading package lists... Done
E: Failed to fetch http://security.ubuntu.com/ubuntu/dists/xenial-security/restricted/source/Sources  Empty files can't be valid archives
E: Failed to fetch http://security.ubuntu.com/ubuntu/dists/xenial-security/universe/source/Sources  Empty files can't be valid archives
E: Failed to fetch http://security.ubuntu.com/ubuntu/dists/xenial-security/multiverse/source/Sources  Empty files can't be valid archives
E: Failed to fetch http://security.ubuntu.com/ubuntu/dists/xenial-security/restricted/binary-amd64/Packages  Empty files can't be valid archives
E: Failed to fetch http://security.ubuntu.com/ubuntu/dists/xenial-security/restricted/binary-i386/Packages  Empty files can't be valid archives
E: Failed to fetch http://security.ubuntu.com/ubuntu/dists/xenial-security/restricted/i18n/Translation-en  Empty files can't be valid archives
E: Failed …